Date: Sun, 27 Mar 2011 00:31:18 +0100 From: Giorgos Keramidas <keramida@ceid.upatras.gr> To: Jim <stapleton.41@gmail.com> Cc: freebsd-questions@freebsd.org Subject: Re: opening a shared object / failing with Undefined Symbol. Message-ID: <AANLkTinSvV-Rt5tWBJASyFcpgHE6gEp8tOp73N4y1MYW@mail.gmail.com> In-Reply-To: <AANLkTi=tyuVJBDN7qRLe7O_a3i3d09sbEis-zoCH14tY@mail.gmail.com> References: <AANLkTi=tyuVJBDN7qRLe7O_a3i3d09sbEis-zoCH14tY@mail.gmail.com>
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On Tue, Mar 22, 2011 at 2:28 PM, Jim <stapleton.41@gmail.com> wrote:
> I have an application that opens two .so files with dlopen(3):
> =C2=A0/usr/local/lib/libag_core.so
> =C2=A0/usr/local/lib/libag_gui.so
>
> Both files exist
> Running nm(1) against each produces a lot of output, showing all the
> symbols I know to exist in each library.
>
> My application gets a null return from dlopen on the libag_gui.so.
>
> dlerror produces the following string:
> =C2=A0"/usr/local/lib/libag_gui.so Undefined symbol "agTimingLock"
>
> $ nm /usr/local/lib/libag_gui.so | grep agTiming
> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 U agTimingLock
>
> I'm guessing that means that agTimingLock is used in that library but
> not defined?
>
> $ nm /usr/local/lib/libag_core.so | grep agTiming
> 0000000000141c00 B agTimingLock
>
> And this would mean that it is defined in libag_core.so?
Yes, but it's in the uninitialized data section:
% man nm
...
"B"
"b" The symbol is in the uninitialized data section (known as BS=
S).
What is the "ag" library? Which version are you using? What sort of
dlopen() call did you try to run?
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